Designing A Poll - Need Your Brilliant Stats Mind!

Hey guys, I'm new here!

I'm creating a poll for my gardening website with a hope of extracting some interesting data. I just want to make sure I don't invalidate the data right away by poorly designing the poll, which at this point is probably an issue since I don't know how to do it.

I'm currently reading up on how to properly design surveys and polls, but thought I'd ask in here, too. The questions will all be multiple choice (1 answer per question). Here's what I have for questions right now.

Which organic gardening topic do you most want to learn about?
Growing Vegetables, Fruits And Other Foods |
Getting Rid Of Insect/Disease Pests And Wee |
Growing Flowers And Other Beautiful Plants

Should farmers and gardeners use genetically modified seeds?
Yes | No | Don't Know

Do you use compost in your garden?
Yes | No | Don't Know

What is your gender?
Male | Female

What is your age?
<20 | 20-39 | 40-59 | 60+

Do you have kids?
Yes | No

Where are you from?
USA | Canada | Elsewhere

I apologize if I haven't given you enough info here to get a good answer, but I'm still not sure exactly what to ask.

Is there anything jumping out at you that is just plain bad poll design? Do I need to do a lot more reading before even trying my hand at this?